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The spacecraft NEAR Shoemaker survived its daring crash-landing onto the
surface of the asteroid Eros earlier this year鈥攂ut its success owed more
to luck than design. Now scientists have found a way to identify good landing
spots on asteroids and comets. G茅rard Medioni at the University of
Southern California in Los Angeles has built a vision system that identifies
craters on the surface of an asteroid and tags them as reference points. The
system measures the relative sizes of the craters, the distance between them,
and how their shapes change with perspective as the asteroid moves. From this it
constructs a detailed three-dimensional model of the asteroid as the craft
orbits it.